Aspartame
It has been claimed that aspartame (NutraSweet or Equal), the artificial sweetener commonly used in soft drinks, causes MS or worsens MS-related symptoms. On this basis, it has been suggested that people with MS should not consume aspartame-containing drinks or foods. The possible connection between aspartame and MS has been raised primarily through articles and discussions on the Internet. Claims have also been made that aspartame provokes other neurologic and psychiatric conditions.
There are limited studies of the effects of aspartame on MS and other neurologic disorders. There is no evidence that MS or MS symptoms are worsened by aspartame. However, we are not aware of any formal clinical studies that have specifically investigated the effects of aspartame on the course of MS or on the severity of MS-related symptoms. Limited scientific studies suggest that aspartame may affect immune system cells, but the significance of these findings for MS is not known.
For other conditions, limited studies indicate that aspartame may provoke migraine headaches and may worsen depression. There is no evidence that aspartame adversely affects people with Parkinson’s disease or epilepsy.
There are biochemical reasons why aspartame is of possible concern. In the body, aspartame is first converted to another chemical, methanol; methanol may then be converted to formic acid, a toxic chemical. However, clinical studies demonstrate that reasonable quantities of diet soft drinks do not contain enough aspartame to substantially increase the blood levels of methanol or formic acid.
Stevia is an herb that is used by some people as a non-sugar sweetner. Stevia (also known as “sweetleaf”) contains a chemical, stevioside, which is indeed about 100 times sweeter than sugar (sucrose). There is limited safety information on stevia. Some studies suggest that stevia may affect male fertility and decrease blood pressure–these effects of the herb are being studied. Currently, the FDA allows stevia to be imported as a dietary supplement, and one review of the safety information about stevia concluded that it was “possibly safe”. Of note, stevia may cause allergic reactions in people who are allergic to plants in the Asteraceae/Compositae family, which includes ragweed, chrysantemums, marigold, and daisies.
In conclusion, one can state that there is “no evidence” that aspartame affects MS and MS-associated symptoms. However, there is “no evidence” about any aspect of aspartame use and MS since no research studies have been conducted in this area. Clearly, further research is needed to provide a definite answer as to whether aspartame has any harmful effects on people with MS.